Emergency services have rushed to Kaiapoi Mill in Canterbury where one person was trapped under machinery and freed by firefighters.

A Fire and Emergency New Zealand (FENZ) spokesman confirmed they had been called to the worksite on Ranfurly St with reports that somebody was trapped by the leg.

They had worked to free the person "under the guidance of St John", he said.

FENZ were called about 1.40pm and the person was freed by 2.25pm, he said.

A St John spokeswoman confirmed they had sent an ambulance and a rapid response vehicle to a "workplace incident".

The person was transported to Christchurch Hospital with moderate injuries.

Police were also called at 1.40pm.